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Fad Diets, Detoxes and Cleanses

Over half of all Canadian adults are overweight or obese.1 Being overweight or obese is associated with an increase in many chronic diseases, such as hypertension, type 2 diabetes, cardiovascular disease, osteoarthritis and some types of cancer.1 Many of these people have attempted or will attempt to lose weight to improve their health. The constant saturation of the market and the media with endless diet and weight loss claims makes it difficult for the average Canadian to identify sound nutritional advice.


Fad Diets

A fad diet is a popular diet that generally promises quick weight loss.2 They are generally very restrictive, often under 800 calories, and do not follow evidence-based healthy eating guidelines.2 They are also frequently suboptimal in many nutrients, such as dietary fibre, carbohydrates, vitamins, minerals, and protective phytochemicals.3 Fad diets, and the products they recommend, can also be dangerous to a person’s health as they may promote malnutrition, nutrient imbalances and weight cycling.2 People will often initially report losing weight, however, the restrictive nature of fad diets is not sustainable long-term and many people regain the lost weight, and often some extra weight, once they liberalize their diet. Weight cycling may actually be more detrimental to a person’s health than simply remaining overweight or obese.4

Healthcare providers can help their patients identify fad diets by looking for some of the following red flags.3

  • Promises weight loss of more than two pounds (1 kg) per week.
  • Does not provide support for long-term weight loss success.
  • Restricts you to less than 800 calories a day.
  • Is rigid and does not fit into your lifestyle or state of health.
  • Cuts out major food categories (like gluten or carbohydrates) and stops you from enjoying your favourite foods.
  • Forces you to buy the company’s foods or supplements rather than show you how to make better choices from a grocery store.
  • Uses “counsellors” who are actually salespeople trying to make a commission from what they sell.
  • Gives you nutrition advice that is based on testimonials rather than scientific evidence.
  • Promotes unproven ways to lose weight such as starch blockers, fat burners and colonic cleanses.
  • Does not encourage physical activity.
  • Recommendations based on a single study.
  • Recommendations based on studies that have not been peer-reviewed.
  • Simplistic conclusions drawn from a complex study.

Diet Detoxes and Cleanses

Diet detoxes and cleanses claim to help improve intestinal health, promote weight loss and remove ‘toxins’ ingested through the food/drinks we consume and the air we breathe.5 There is little scientific evidence that detox diets and cleanses actually promote these results.5 Many diet detoxes and cleanses are extremely restrictive and are not based on scientific evidence. These are generally meant to be short-term programs; however, they are often nutritionally insufficient.


The body naturally removes waste through our kidney, liver, lungs, and intestines.5 Detox diets or cleanses can be particularly dangerous, especially if followed for long periods of time, as they can cause side effects, such as cramping, bloating, nausea, diarrhea, dehydration, vomiting, headaches, lack of energy and dizziness.5 Furthermore, diet detoxes and cleanses may lead to more serious health conditions, such as changes in electrolyte levels, dehydration, low blood sugar, low or high blood pressure, and vitamin and mineral deficiencies.5

Popular Fad Diets, Detoxes and Cleanses

*Note: this is not a comprehensive list and includes only a few examples of popular diets.

  • Paleo Diet – basis is on the consumption of foods thought to be predominately consumed during the Paleolithic era (typically includes vegetables, fruits, nuts, roots, meats). The restrictive nature of the paleo diet may produce some weight loss, however, the diet is usually not sustainable long-term and most people will regain any weight lost. It is also challenging to meet requirements for fibre, calcium and vitamin D, among other nutrients when following the paleo diet.6
  • Ketogenic Diet – high fat, adequate protein and low carbohydrate diet with a goal of triggering ketosis (burning of fat for energy rather than carbohydrate). This diet has been used medically to treat severe, refractory epilepsy in children with success; however, it has become a mainstream diet trend with claims to promote weight loss and improve overall health. Often people will experience rapid weight loss when first implementing the diet; however, this is generally water loss.7 It is difficult to meet requirements for some nutrients, such as fibre, calcium and vitamin D, when following this diet.7 Some research has suggested that a ketogenic diet may be useful in treatment of some cancers and type 2 diabetes; however, more research is needed, especially on the long-term effects of the diet.
  • Gluten-free Diet – removes all source of gluten from the diet. For people diagnosed with celiac disease or gluten intolerance, a gluten-free diet is crucial in maintaining optimal health; however, a gluten-free diet has been promoted as a diet for everything from weight loss to improving skin condition. The wheat belly diet is a variation of the gluten-free diet suggesting that the production of wheat (and other gluten-containing grains, like barley and rye) has changed over the past decades and, due to genetic modifications, modern day wheat is the cause of many health concerns. There is no research to verify claims that a gluten-free diet is needed in the absence of celiac disease.
  • Juice Cleanses – generally, these include the consumption of four to eight bottles of juice per day for three to seven days. The juices are purchased from certain companies that make a variety of health claims, such as improve circulation, promote weight loss, and decrease inflammation; however, these claims are generally not supported by any scientific evidence. Some plans may allow for some solid foods during a cleanse, but typically the juices are the primary source of nutrition. Generally, these cleanses are high in sugar, low in calories, and suboptimal in many nutrients.6

Advice for Patients to Help Promote Weight Management

Healthcare providers should discuss realistic weight loss goals (i.e. 1-2 lbs (0.45-0.9 kg) per week) with any patients interested in losing weight. The dangers of fad diets, detoxes and cleanses should also be discussed with patients. Most importantly, remind patients that if a diet sounds too good to be true, it mostly likely is. Alternatively, healthcare providers should provide patients with information about healthy weight management. Some tips include:

  1. Eat a healthy diet that includes three meals and one to three snacks per day. Canada’s Food Guide can be used to help with meal planning.
  2. Physical activity is an important component of a healthy lifestyle and weight management. Adults aged 18-64 should be encouraged to participate in at least 150 minutes of moderate to vigourous physical activity per week. Physical activity guidelines are available for Canadians of all ages.
  3. If considering a weight loss program, patients should critically review the program to ensure that it is nutritionally complete and aims to promote long-term sustainable weight loss.
  4. Consider a referral to a Registered Dietitian to assist patients with meal planning, label reading, grocery shopping and portion size to promote weight management.
Date of creation: December 22, 2017
Last modified on: November 26, 2019


1Statistics Canada. (2015, November 27). Overweight and obese adults (self-reported), 2014. Retrieved from
2Dietitians of Canada - Unlock Foods. (2017, October 18). Get the Facts on Fad Diets. Retrieved from
3Cleveland Clinic. (2017, March 31). Fad diets. Retrieved from
4Strohacker K, Carpenter K, and McFarlin B. (2009). Consequences of Weight Cycling: An Increase in Disease Risk? International Journal of Exercise Science. 2(3): 191-201.
5Dietitians of Canada - Unlock Food. (2017, November 9). Will Bowel Cleansing Help me Lose Weight and Keep my Digestive System Healthy? Retrieved from
6Dietitians of Canada - Unlock Food. (2017, October 18). Will the Paleo diet help me lose weight? Retrieved from
7HealthLink BC. (2017, March 21). Ketogenic Diet: Is going low carb healthy? Retrieved from